Monoazo dyestuff and process of making same.



UNITED STATES PATENT OFFICE.

OTTO ERNST AND HEINRICH EICHWEDE, OF HOCHST-ON-THE-MAIN, GERMANY, AS-SIGNORS, TO FARBWERKE VORM. MEISTER LUCIUS 8t BRITNING, F HOCHST-ON-THE-MAIN, GERMANY, A CORPORATION OF GERMANY.

MONOAZO DYESTUFF AND PROCESS OF MAKING SAME.

No Drawing.

Patented Feb. '7, 1911.

Application filed May 25, 1910. Serial No. 563,328.

To all whom it may concern:

Be it known that we, O'rro ERNST, Ph. D.,

. chemist, and HEINRICH EIGHWEDE, Ph. D.,

chemist, citizens of the Em ire of Germany, residing atHochst-on-theain, Germany, have invented certain new and usefulImprovements in Monoazo Dyestuffs and Processes of Making the Same, ofwhich the fol- .fdipafile hth l, a product is obtained possessin morevaluable properties than the dyestuif erived from the combination withvB-naphthol. In the first place, the shade of the color-lakes producedfrom the new dyestuff has a bluer hue and is exceedingly pure andbright. Furthermore, by substituting the B-oxynaphthoic acid for the ,8-naphthol, the fastness of the new dyestuff to light is greatly enhancedso that the invention of this dyestufi constitutes a great technicaladvance as compared with the combination described in U. S. Patent No.

In carrying out the newprooess we can proceed as follows: 22.15 arts byweight ofthe aforesaid chlorotolui in-sulfonic acid are converted in theusual manner into the diazo-compound which, for the most part,-

separates upon its formation. This susension of the diazo-sulfonic acidis run into a solution of 20 parts of fi-oxynaphthoic acid of meltingoint 216 together with 26 parts of calcin soda in the necessary quantityof water, whereupon nearly the whole ofthe dyestufi separate. The massis then gently heated for some time and a small quantity of a saturatedsolution of common salt is added to it in order to completely separatethe dyestufi'. The finely divided dyestuii is of a bright-red color. Ofcourse, the preparation of the dyestufi and its conversion in tocolor-lakes may be carried out in a single operation by adding to theliquids to be combined a substratum or a precipitating agent, such asbarium-chlorid, strontiumchlorid or the like, or by first forming thefree acid of the dyestufi according to the method considered to besuitable for the preparation of the color-lakes. In this operation aswell as in the subsequent transformation of the dyestufi' into lakes,Turkeyred oil or some similar fixing agent may be used.

Having now particularly described our invention, what we claim'is:

1. The process of manufacturing a red monoazo dyestufl', which consistsin combining the 5-diazo-2-chloro-toluene-asulfonic acid with,B-oxynaphthoic acid of melting point 216.

2. As a new product, the monoazo dyestufl', obtainable from5-diazo-2-chlorotoluenet-sulfonic acid by combinin it withB-oxynaphthoic acid of melting polnt 216, being, in form of its sodiumsalt, when dry, a red powder, insoluble in alcohol, but dissolving inwater with a yellowish-red color, from which solution the dyestuif isprecipitated as a dark-red precipitate by means of mineral acids;yielding bright-red colorlakes of eat fastness to light.

In testimony whereof, we afiix our signatures in presence of twowitnesses.

OTTO ERNST. HEINRICH EICI-IWEDE.

Witnesses:.

J EAN GRUND, CARL Gaunn.

